Java中带复选框的树（Java CheckBox Tree）的实现和应用 - JAVA

else
yLabel = (dCheck.height - dLabel.height) / 2;
check.setLocation(0, yCheck);
check.setBounds(0, yCheck, dCheck.width, dCheck.height);
label.setLocation(dCheck.width, yLabel);
label.setBounds(dCheck.width, yLabel, dLabel.width, dLabel.height);
}

@Override
public void setBackground(Color color)
{
if(color instanceof ColorUIResource)
color = null;
super.setBackground(color);
}
}
在CheckBoxTreeCellRenderer的实现中，为了处理背景色等问题，我们重新实现了一个JLabel的子类CheckBoxTreeLabel，其源代码如下：

package demo;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;

import javax.swing.Icon;
import javax.swing.JLabel;
import javax.swing.UIManager;
import javax.swing.plaf.ColorUIResource;

public class CheckBoxTreeLabel extends JLabel
{
private boolean isSelected;
private boolean hasFocus;

public CheckBoxTreeLabel()
{
}

@Override
public void setBackground(Color color)
{
if(color instanceof ColorUIResource)
color = null;
super.setBackground(color);
}

@Override
public void paint(Graphics g)
{
String str;
if((str = getText()) != null)
{
if(0 < str.length())
{
if(isSelected)

g.setColor(UIManager.getColor("Tree.selectionBackground"));
else
g.setColor(UIManager.getColor("Tree.textBackground"));
Dimension d = getPreferredSize();
int imageOffset = 0;
Icon currentIcon = getIcon();
if(currentIcon != null)
imageOffset = currentIcon.getIconWidth() + Math.max(0, getIconTextGap() - 1);
g.fillRect(imageOffset, 0, d.width - 1 - imageOffset, d.height);
if(hasFocus)
{
g.setColor(UIManager.getColor("Tree.selectionBorderColor"));
g.drawRect(imageOffset, 0, d.width - 1 - imageOffset, d.height - 1);
}
}
}
super.paint(g);
}

@Override
public Dimension getPreferredSize()
{
Dimension retDimension = super.getPreferredSize();
if(retDimension != null)
retDimension = new Dimension(retDimension.width + 3, retDimension.height);
return retDimension;
}

public void setSelected(boolean isSelected)
{
this.isSelected = isSelected;
}

public void setFocus(boolean hasFocus)
{
this.hasFocus = hasFocus;
}
}

通过定义CheckBoxTreeNode和CheckBoxTreeCellRenderer。我们解决了CheckBoxTree和JTree的两个根本差异，但是还有一个细节问题需要解决，就是CheckBoxTree可以响应用户事件决定是否选中某个结点。为此，我们为CheckBoxTree添加一个响应用户鼠标事件的监听器CheckBoxTreeNodeSelectionListener，该类的源代码如下：

package demo;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.JTree;
import javax.swing.tree.TreePath;
import javax.swing.tree.DefaultTreeModel;

public class CheckBoxTreeNodeSelectionListener extends MouseAdapter
{
@Override
public void mouseClicked(MouseEvent event)
{
JTree tree = (JTree)event.getSource();
int x = even

Java中带复选框的树（Java CheckBox Tree）的实现和应用(四)